DNA-synthesizing complexes are components of human, bovine and rooster spermatozoa. Their presence in all human ejaculates examined plus the existence of autoantibodies to the complex-associated DNA polymerase in some individual members of infertile marriages suggests that these complexes are normal sperm components and that they are synthesized at a stage of spermatogenesis subsequent to the sequestering of the developing sperm from the immune system. We propose a multi-faceted approach designed to ascertain their function and to determine their involvment in antibody and/or immune complex formation in infertility or following vasectomy. Comparative studies will be performed on spermatozoa from a variety of vertebrate species in order to delineate the phylogenetic occurrence of DNA-synthesizing complexes and associated DNA polymerases. Sera from large numbers of persons of questionable fertility, as well as from vasectomized or intact men will be screened for the presence of antibodies to the sperm DNA-synthesizing complex or to the baboon type-C retrovirus. Immune complexes present in the sera of vasectomized or infertile individuals will be purified, dissociated and attempts made to identify sperm antigens as well as antibodies to sperm components. The results obtained will increase our knowledge of the phylogeny of a specific sperm nuclear component as well as delineate possible correlation between specific sperm antibodies, immune complexes and infertility.